In the batching of the materials for concrete, the cementitious materials such as portland cement and fly ash are normally proportioned by weight accumulatively in a suspension hopper scale. This free fall from overhead storage or from conveyors results in considerable dusting of materials as air is displaced within the weigh hopper. There is further dusting of the cementitious materials as they are released from the weigh hopper and combined with aggregate materials and water to form concrete in a mixer. This exhausting of dust due to the dry batching of materials is a contaminant to the environment and must be filtered or drawn to a bag house for confinement and recycling.
Normally, suspension hopper scales for cementitious materials are located beneath a storage silo and having a cone shaped or pyramidal base are excessively high in vertical dimensions so as to contain the necessary volume of materials. The mixing of a slurry of cementitious materials and water is normally accomplished in a separate vessel.